Thi sis the second stage in building the 16 step sequencer. this proof of concept shows the rotary encoders being used to set each step note. At the moment this is sending a midi to ableton live. In this test, each note is taken from a scale array, when the rotary knob increases or decreases, it moves through the scale array values. This array was C major. Fixed at the moment, but selectable later. The test also looks at step loop length, going from one, two, and four steps by reading the analogue value from the potentiometer. The proof also uses a potentiometer to adjust the clock speed and send this to ableton live. These rotary encoders have built in RGB leds, the code changes between blue and red to signify it the step note should be played or silent.
This setup uses MCP23S17 port expanders. These are SPI based, and work on a single chain, with each of the MCP chips having a separate hardware address. The chain length is limited to 8 chips, but each chip has enough GPIO pins to cater for two of the rotary encoders. These RGB Rotary encoders are from Sparkfun.
There are still some issues with the smoothness of the rotary encoders. I will need to review the code that assess increments, as well as looking at whether each of the interrupts is working. Further work is also required to deal with more than one interrupt being fired at the same time.
Also, need to resolve potential issue with using the WS2811 leds with a library that might clash with interrupts.
